Packaging for Bulk Goods, Particularly Bag Made of Plastic Film

ABSTRACT

Disclosed is a packaging ( 1 ) for bulk material, especially a bag made of plastic film, comprising a packaging wall ( 2 ) which envelops the bulk material and is provided with at least one multilayered wall area ( 6 ) that is composed of at least one inner layer ( 7 ) and at least one outer layer ( 8 ). Each layer has at least one air-permeable planar piece ( 9 ). At least one conducting element ( 12 ) for the air flow that penetrates the air-permeable planar pieces is disposed between the inner layer ( 7 ) and the outer layer ( 8 ). The conducting element ( 12 ) is embodied as at least one section of an airtight intermediate layer which is arranged such that at least the air-permeable planar pieces ( 9 ) of the inner layer ( 7 ) and/or the outer layer ( 8 ) are covered.

The invention relates to a packaging for bulk goods, particularly a bagmade of plastic film, having a packaging wall that sheathes the bulkgoods, and at least one wall region configured in multiple layers, madeof at least one inner layer and at least one outer layer, whereby eachlayer has at least one air-permeable planar piece.

Known packagings are sacks or bags made of a film, particularly aplastic film, which serve to wrap widely different kinds of bulk orfilled goods, such as cement, fertilizer, or similar products, which areproduced in the construction materials industry or the chemicalindustry, for example.

During the filling process of known packagings, a correspondingproportion of air gets into the interior of the packaging along with thefilled goods, thereby causing an excess pressure to occur on the insideof the packaging wall. In order to prevent that the packaging wall isdamaged and/or might tear open as a result of the excess pressure thatis applied to the inside, or that palleting is made more difficult asthe result of the air cushion enclosed in the interior of the packaging,sufficient ventilation from the packaging interior must always beassured. In EP 444 261, a packaging is described that is particularlyused for accommodating filled goods in the form of fine dust. The knownpackaging has a two-layer region provided with perforations, forventilation, by way of which the excess pressure prevailing in theinterior of the packaging can be reduced. If the perforations of theinner and outer wall are disposed so that they cover one another, solidparticles of the filled goods can also exit, along with the escaping airstream. The exit of smaller solid particles, in the form of dust, fromthe packaging, can be prevented by using a filter that is disposed inthe two-layer region of the packaging. However, the use of filtermaterial always means increased cost expenditure, and, at the same time,a more complicated design configuration of the packaging.

The invention is based on the task of improving a packaging of theaforementioned type, in such a manner that not only a simplified designconfiguration but also optimal ventilation are guaranteed, and, at thesame time, the filled material is prevented from escaping in the form ofdust.

The solution for this task is accomplished, according to the invention,by means of a packaging for bulk goods having the characteristics ofclaim 1. Advantageous further developments and embodiments of theinvention are indicated in the dependent claims.

In the case of a packaging for bulk goods, particularly bag made ofplastic film, having a packaging wall that sheathes the bulk goods,which wall has at least one wall region configured in multiple layers,made of at least one inner layer and at least one outer layer, wherebyeach layer has at least one air-permeable planar piece, it is provided,according to the invention, that at least one guide organ for the airstream that passes through the air-permeable planar pieces is disposedbetween the inner layer and the outer layer.

The guide organ disposed according to the invention influences the flowof the air escaping from the packaging interior, so that astraight-line, i.e. direct air passage through the wall region of thepackaging wall that is configured in multiple layers, and the relatedexit of solid particles of the filled goods in the packaging areadvantageously prevented. The great change, i.e. deflection of the flowof the escaping air stream brings about the result of almost completeprecipitation of the solid particles out of the air stream that passesthrough the wall region configured in multiple layers, because of thegreater mass inertia of the solid particles. For example, it is possiblethat multiple guide organs, disposed interlaced relative to one another,are present in the wall region configured in multiple layers, formingregions that overlap one another.

According to a first advantageous further development of the invention,it is provided that the guide organ is at least one section of anair-impermeable intermediate layer, which is disposed in such a mannerthat at least the air-permeable planar pieces of the inner layer and/orof the outer layer are covered by the intermediate layer. Each sectionof the air-impermeable intermediate layer, which can be a film, forexample, furthermore also serves as a baffle surface or precipitationorgan for the solid particles carried out with the escaping air stream.As a result of the intermediate layer, which projects into the airstream, and the related deflection of the air stream, areas withstronger flow, i.e. turbulences, and areas with weaker flow are formedin the multi-layer wall region. Particularly in the regions with areduced flow velocity, the kinetic energy of the air stream is no longersufficient to carry the solid particles along, because of their mass. Amajor portion of the solid, i.e. dust particles therefore settlesprimarily in the areas of the multi-layer wall region that have a weakerflow. The air stream, which is thereby almost completely freed of solidparticles, exits into the surroundings by way of the air-permeableplanar pieces of the outer layer, after it has flowed around theintermediate layer. Furthermore, the penetration of moisture from theoutside into the interior of the packaging is advantageously made moredifficult by the intermediate layer, which covers the air-permeableplanar pieces of the inner and outer layer.

The guide organ is preferably formed by a folded-down edge of a flat webthat forms the packaging wall, folded in the longitudinal direction. Theguide organ is therefore part of the packaging wall, and folding downthe edge region of the flat web allows the creation, in advantageouslysimple manner, of such a guide organ, disposed between the layers of themulti-layer wall region. The guide organ, which preferably extendscontinuously in the longitudinal direction of the packaging, guaranteesoptimal coverage of the air-permeable planar pieces of the inner andouter layer of the multi-layer wall region, which are disposed congruentto one another, if possible.

It is also possible that the guide organ is configured as a film stripdisposed separately between the inner and outer layer of the wall regionconfigured in multiple layers. Such film strips can advantageously bedisposed extending both in sections and over the entire length of thewall region configured in a double layer, between the inner and outerlayer. Using a gluing method, for example, the film strip can then befixed in place on at least one of the layers of the multi-layer wallregion, by way of one of its longitudinal sides.

It is furthermore provided that pre-determined partial surfaces of theguide organ are connected, at least in sections, with at least one ofthe layers of the multi-layer wall region. By way of such a connection,according to the invention, between corresponding partial surfaces ofthe guide organ and a layer, in each instance, the guide organ can befixed in place, in advantageously simple manner, in the multi-layer wallregion. Furthermore, in this way, two longitudinal sides around whichthe air stream can flow can be formed on the guide organ, so thatimproved ventilation during filling of the packaging is advantageouslyguaranteed. Preferably, a material-fit connection can be provided bothbetween the inner layer and the related partial surfaces of the guideorgan, in each instance, and between the outer layer and the relatedpartial surfaces of the guide organ, in each instance.

The packaging wall is a folded flat web, whose edge regions, whichoverlap one another, form a multi-layer wall region. Simple productionof the packaging wall that accommodates the filled goods is madepossible by means of the folded flat web. The layers of the multi-layerwall region, produced by means of the edge regions that overlap oneanother, can be fixed in place relative to one another, in a desiredarrangement, by means of a material-fit connection such as weldingand/or gluing, for example. At the same time, sufficient strength isprovided in the connection region of the packaging wall, by way of thematerial fit, so that the excess pressure that occurs in the packaginginterior during the filling process can advantageously be absorbed overthe entire packaging wall, without causing impairments. For example, itis also possible to produce the packaging wall from a film tube producedby means of extrusion blow-molding.

Furthermore, the inner layer of the multi-layer wall region can beformed by means of a material strip that is disposed in the interiorregion of the packaging. The production of the packaging is furthersimplified by disposing the material strip, which particularly extendsin the longitudinal direction of the packaging, on the inside of thepackaging, particularly one formed from a flat web. In this connection,the material strip completely covers the guide organ, formed as a filmstrip, for example, and can be connected with the packaging wall bymeans of a glue connection or weld connection, in each instance, overits entire length, in the region of the two side edges.

According to a further development of the invention, the possibilityalternatively exists that the guide organ is formed from a part of afolded film strip that is disposed on the outside or inside of a filmtube that forms the packaging wall, running in the longitudinaldirection of the packaging, in order to form the multi-layer wallregion. A separate film strip, folded in such a manner, can be producedusing a simple production process, such as plastic extrusion, forexample. Furthermore, the film strip produced, whose other part formsthe outer or inner layer of the multi-layer wall region, in eachinstance, can be permanently connected with the film tube by means of ajoining method, such as gluing or welding, for example, inadvantageously simple manner. A material-fit connection, for exampleconfigured as a glued connection, can serve to form a firm connectionbetween film tube and film strip. It is possible, for example, to use afilm strip produced from plastic film as a guide organ, which strip isbrought into a connection with a film tube, also produced from plasticfilm.

Each packaging wall has perforations in the air-permeable planar pieces,which are preferably configured as rows of circular holes and/or slitsin the inner and outer layer, respectively. Using the perforations, asimple design configuration of an air-permeable planar piece isprovided, whereby the perforations are made in the packaging wall, whichis preferably configured as a plastic film, by way of correspondingneedling or cutting tools. In this connection, the perforations can havedifferent dimensions in the inner and outer layer of the packaging wall.

At least one spacer is disposed at least in partial regions of theair-permeable planar pieces of each layer and/or of the guide organ.Each spacer additionally improves the escape of the air that got intothe packaging along with the filled goods, from the packaging interior.The spacers are preferably disposed between the guide organ configuredas an intermediate layer, and an adjacent layer, in each instance, sothat adhesion forces between the adjacent surfaces of the guide organand the layers cannot occur. Such attraction forces can prevent passageof the air stream.

According to a further development of the invention, each spacer can beconfigured as an embossing made in the layers and/or the guide organ.The embossings, preferably formed in the longitudinal direction of thepackaging, in the multi-layer wall region of the packaging wall, createan advantageously simple possibility for maintaining a distance betweentwo film webs that touch one another, for example. The plastic andpermanent deformation of the layers required for the production of anembossing can take place in advantageously simple manner, by means ofembossing tools. The embossings can be made both in sections andcontinuously, in partial regions of a flat web, for example, which canbe used to form the packaging wall.

Exemplary embodiments of the packaging according to the invention, fromwhich additional inventive characteristics are evident, are shown in thedrawing. This shows:

FIG. 1: a perspective view of a first exemplary embodiment of apackaging according to the invention;

FIG. 2: a view of the first exemplary embodiment according to FIG. 1 incross-section, and

FIG. 3: a view of a second exemplary embodiment of a packaging accordingto the invention, in cross-section, and

FIG. 4: a view of another exemplary embodiment of a packaging, incross-section.

FIG. 1 shows side-fold bag 1, whose packaging wall 2 can be closed off,with material fit, both in the bottom region 3 and in the head region 4,particularly by means of a weld 5, 5′. The packaging wall 2 has a wallregion 6 configured with multiple layers (FIG. 2), which is formed froman inner layer 7 and an outer layer 8. The inner layer 7 and the outerlayer 8 have an air-permeable planar piece 9, in the longitudinaldirection of the packaging, in each instance. The air-permeability ofthe layers 7, 8 is guaranteed by means of 10 perforations made in themas holes, which allows exit of the air that got into the packaginginterior 11 during the filling process. So that solid particles of thebulk goods filled in do not exit from the packaging interior togetherwith the escaping air stream, an intermediate layer 12 is disposedbetween the layers 7, 8 of the wall region 6 configured in multiplelayers. The intermediate layer 12 takes over the function of a guideorgan for the escaping air stream, and, at the same time, aprecipitation organ for the solid particles of the filled goodsentrained in the air stream. In order to prevent occlusion of theperforations 10 in the layers 7, 8, as the result of adhesion forcesthat might be in effect between the layers 7, 8 and the intermediatelayer 12, spacers configured as embossings 13 are disposed inpredetermined partial regions of the layers 7, 8. By means of theperforation 10 and the embossings 13, which are preferably configuredtogether in a planar piece of a layer 7, 8, in each instance, optimalventilation of the packaging interior 11 is guaranteed at all times.

FIG. 2 shows the cross-section of the bag 1 according to the invention,according to FIG. 1, and is specifically intended to illustrate itsstructure. The packaging wall 2 is particularly produced from a materialweb that has been laid together, the edge regions of which form theoverlap region having the multi-layer wall region 6. The intermediatelayer 12, which is disposed between the inner layer 7 and the outerlayer 8, is formed from a folded-down edge of the material web thatforms the packaging wall 2. In order to be able to firmly connect thefolded material web, particularly the edge regions, with one another inthe overlap region, multiple material-fit connections 14, 14′ areprovided in the multi-layer wall region 6.

Another exemplary embodiment of a bag 15 according to the invention isshown in the cross-section of FIG. 3. In this connection, the packagingwall 16 is formed from a tubular film produced by means of an extrusionmethod, on which film a separate, folded film strip 18 is disposed, onits outside, in the longitudinal direction of the packaging to form themulti-layer wall region 17. The multi-layer wall region 17 produced inthis way again has an inner layer 19, an intermediate layer 20, an outerlayer 21, whereby the intermediate layer 20 and the outer layer 21 areparts of the film strip 18, and the inner layer 19 is part of thetubular film that forms the packaging wall 16. In order to guarantee afirm connection between the folded film strip 18 and the packaging wall16 configured as a film tube, material-fit connections 22, 22′ areformed between film strip 18 and packaging wall 16; these can beproduced, for example, by means of a welding or gluing process. Ofcourse, the inner layer 19 and the outer layer 21 of the bag 15, likethe bag 1 in FIG. 1, also have perforations and embossings forventilation; for the sake of simplicity, these are not shown.

FIG. 4 shows another possible embodiment of a bag 23, which is shown incross-section, in order to makes its structure clear. The packaging wall24 is produced from a flat web that has been laid together, the edges ofwhich are connected with one another by way of a material-fit connection25. To form the multi-layer wall region 26, a material web has beenapplied to the inside of the packaging wall 24, and forms the innerlayer 27 of the bag. A firm connection between the inner layer 27, whichis configured as a material strip, and the packaging wall 24 is assuredby way of the material-fit connections 28, 28′. An intermediate layer 30configured as a separate film strip is introduced between the innerlayer 27 and the outer layer 29, and the air stream that passes throughthe multi-layer wall region flows around it. In this connection, theintermediate layer 30 is attached to the layers 27, 29 of themulti-layer wall region, with predetermined partial regions, by way ofthe material-fit connections 31, 31′, in such a manner that theintermediate layer forms two longitudinal sides around which the airstream flows.

1: Packaging for bulk goods, particularly bag made of plastic film,having a packaging wall that sheathes the bulk goods, which wall has atleast one wall region configured in multiple layers, made of at leastone inner layer and at least one outer layer, whereby each layer has atleast one air-permeable planar piece, wherein at least one guide organfor the air stream that passes through the air-permeable planar pieces(9) is disposed between the inner layer (7, 19, 27) and the outer layer(8, 21, 29). 2: Packaging according to claim 1, wherein the guide organis at least one section of an air-impermeable intermediate layer (12,20, 30), which is disposed in such a manner that at least theair-permeable planar pieces (9) of the inner layer (7, 19, 27) and/or ofthe outer layer (8, 21, 29) are covered. 3: Packaging according to claim1, wherein the guide organ is formed by a folded-down edge of a flat webthat forms the packaging wall (2), folded in the longitudinal direction.4: Packaging according to claim 1, wherein the guide organ is a separatefilm strip that runs between the layers (27, 29) of the multi-layer wallregion (26), in the longitudinal direction of the packaging. 5:Packaging according to claim 4, wherein pre-determined partial surfacesof the guide organ are connected, at least in sections, with at leastone of the layers (27, 29) of the multi-layer wall region (26). 6:Packaging according to claim 3, wherein the packaging wall (2) is afolded flat web, whose edge regions, which overlap one another, form themulti-layer wall region (6). 7: Packaging according to claim 4, whereinthe inner layer (27) of the multi-layer wall region (26) is formed bymeans of a material strip that is disposed in the interior region of thepackaging. 8: Packaging according to claim 1, wherein the guide organ isformed from a part of a folded film strip (18) that is disposed on theoutside or inside of a film tube that forms the packaging wall (16),running in the longitudinal direction of the packaging, in order to formthe multi-layer wall region (17). 9: Packaging according to claim 1,wherein the packaging wall has perforations (10) in the air-permeableplanar pieces (9). 10: Packaging according to claim 1, wherein at leastone spacer is disposed at least in partial regions of the air-permeableplanar pieces (9) of each layer (7, 8, 19, 21, 27, 29) and/or of theguide organ. 11: Packaging according to claim 1, wherein each spacer isconfigured as an embossing (13) made in the layers (7, 8, 19, 21, 27,29) and/or the guide organ.